Here is the optimized solution in Java. Copy or view it below.
Java
package Problems_On_Number;
import java.util.Scanner;
public class HarshadCheck {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("enter the number:");
int n = sc.nextInt();
int dummy = n;
int sum = 0;
while (n > 0) {
sum += n % 10;
n /= 10;
}
if (dummy % sum == 0) {
System.out.println("it is a harshad number.");
} else
System.out.println("it is not a harshad number.");
sc.close();
}
}